1. Field of the Invention
The present invention relates to a novel 4-hydroxypyridine derivative useful as a vasodilator and vasodepressor, a method for preparing the 4-hydroxypyridine derivative, and a pharmaceutical composition comprising the derivative.
More specifically, the present invention relates to a 4-hydroxypyridine derivative represented by the following formula (I): ##STR2## wherein R represents a methyl group or an isopropyl group. The present invention also relates to a method for preparing the 4-hydroxypyridine derivative comprising the step of cultivating a microorganism, a pharmaceutical composition comprising an effective amount of the derivative, and a method for treating circulatory diseases comprising the step of administering the derivative.
2. Description of the Related Art
Yoshida et al. (Argic. Biol. Chem., 41: 849-862, 1977) discloses a series of Piericidins represented by the following formulas: ##STR3## wherein R.sub.1 represents a hydrogen atom or a methyl group, and R.sub.2 represents a methyl group or an isopropyl group.
Yano et al. (J. Antibiotics 39: 38-43, 1986) discloses series of Actinopyrones represented by the following formula: ##STR4##
The physicochemical properties of Piericidins and Actinopyrones are similar to those of the 4-hydroxypyridine compounds of the present invention represented by the above-described formula (I). However, the 4-hydroxypyridine compounds of the present invention structually differ from Piericidins, because each Piericidine has two or three methoxyl substituents in its molecule, while both of the compounds of the present invention have only one methoxyl group in thir molecules. Actinopyrones are also not structural analogues of the 4-hydroxypyridine compounds of the present invention, because Actinopyrone is characterized as having a pyrone nucleous, while the compounds of the present invention have a pyridine ring structure.